An Act of Love
by BlueRaven 666
Summary: AU. When Agni discovers Sebastian in heat, he makes a decision that will change their lives and the lives of their masters forever. Agni X Sebastian. WARNINGS: Graphic yaoi, MPreg, Graphic descriptions of birth. Note: MPreg Male pregnancy. Don't like, don't read! PLEASE REVIEW!
1. PART 1

**Part 1**

"Sebastian, tell me, are you a...?"

The smirk that crossed the raven-haired butler's face, combined with the cheeky expression that lingered in his eyes, had been more than enough of an answer for Agni. If it weren't for the fact that they were in the middle of a competition with almost all of London, including the Queen, watching, he would have forgotten about the curry and move to deal with Sebastian immediately. However, as time passed and the day drew to a close, Agni came to realize that the Phantomhive butler wasn't all that bad, even if he was a demon, especially after seeing the effect his curry buns had on those who had eaten the curry that had been laced with _Kali ma._ To think a demon could infuse enough kindness in a bite of food to cure people of the effects of the dreaded spice, and Sebastian didn't seem interested in harming him, the prince, or the earl, and soon Agni found himself growing fond of the idea of becoming and remaining the demon's friend.

Which had probably been another one of the many surprises Sebastian had given him that day.

"A friend? Nobody has ever called me that. You, sir, are the first."

The shocked expression on his face combined with the wonder lingering in his voice made something ache in Agni's chest. Had Sebastian really never had one friend in his whole life? What about Ciel? The two of them were as inseperable as he and Soma, if not more so. Did they not see each other as friends? Sebastian always seemed to be catering to the earl's every want and need, constantly leaping at his every beck and call, and he did it with a spring in his step and a smile on his face. Meanwhile, Ciel always seemed to push away his butler's affections; speaking to him and ordering him around in a flat, disinterested tone, unless the odds were stacked heavily against him; in which case, he was on the verge of screaming at the demon. It was rare for them to be caught looking at each other, and even rarer for them to engage in conversation the way Agni often did with the Prince. Judging from how the two of them treated each other, he could only wager a guess and believe that Ciel merely saw Sebastian as a tool, and that Sebastian merely saw Ciel as a meal held far out of his reach.

It was an assumption that Agni couldn't help but feel relieved in making, though. He'd been fighting it for some time now, but with each day it became harder and harder to deny it: he was developing feelings for Sebastian. How would Prince Soma look at him if he found out? Ashamed? Disgusted? Would he even want him around anymore? And Sebastian. How would he respond if he were to say something? Granted, the demon was always so busy that he never seemed to be all that concerned about having any sort of romantic or sexual relationship with somebody, but something told Agni that he was more interested in women, if he were given a choice, so he forced himself to keep his feelings to himself.

That is until one afternoon found Sebastian and Ciel visiting the townhouse as they scanned the city for clues on their most recent case from the Queen. While Soma was spending every waking moment trying to get Ciel to spend time with him, Agni's eyes were fixated on Sebastian as he approached him with a friendly smile. He couldn't quite put his finger on it, but something felt... _off_ about the butler. He wasn't sure what, but it almost looked like he was distracted by something, his ears perking and head swiveling at minute sounds that Agni couldn't hear. He seemed tired, as well; foggy in the eyes, his steps slow as his knees wobbled, and his shoulders hunched over in a way that made him think he'd just got done fighting an army.

"Is everything all right, Sebastian?" Agni asked as the demon came closer.

The Phantomhive butler hesitated for a fraction of a second before he curtly replied, "Yes, everything is fine."

Even his voice was off; softer and heavy, as if he had said it while running. It was a farcry from the strong, unwavering confidence that normally carried in his tones; the voice that left Agni shivering with excitement, giving him goosebumps whenever he heard it. Somethimg was definitely wrong, but it didn't look like Sebastian was willing to discuss the matter at all.

For a time, Agni contented himself with engaging in small conversation with the demon as they filled each other in on what they and their masters had been up to since they last saw each other. However, it quickly became apparent to him that Sebastian's "condition" was more extensive than just being distracted and fatigued. Gradually, the smile fell and sweat began to glisten along his brow. For the first time since Agni had met him, he looked genuinely ill.

"Sebastian, I think you should take a moment to rest," he piped up, "You're as pale as death. I'm sure whatever Master Ciel needs, I'll be able to fetch it for him."

An unsure hum droned from within the demon's throat as he craned his neck in search of his master. He found him trying feebly to push Soma off as the prince squeezed him in a hug, one that Ciel had been trapped in for the entire length of the two butlers' conversation. The earl had already stated that they were done investigating for the day, so there wouldn't be a need for the demon to accompany him until tomorrow. There was just a matter of preparing dinner and tea for him before he retired for the night, tasks that Agni was more than capable of doing.

"Very well," Sebastian finally piped up, "but only for a couple of hours, so I can clear my head."

"Take as much time as you need," Agni urged, "Ciel will be in capable hands until you're well again."

Sebastian only gave him a curt nod before he turned a corner and disappeared out of sight, and Agni waited until his footsteps had faded away to silence before directing his attention back to their masters. When he tried explaining the situation to Ciel, the earl became defiant; urging him to bring Sebastian back, no matter what state he might be in. What he didn't account for was Prince Soma standing by his buter's decision as he went on about how Sebastian should be in top physical health before he could think about taking care of him. While it was daunting to hear the two of them talk about the butler as if he were human, the earl was willing to give them the benefit of the doubt and went along with it, much to Agni's relief.

 **000**

Agni's brow knitted with concern as he wandered the quiet halls of the townhouse.

It'd been several hours since he'd asked Sebastian to lie down and rest. Prince Soma and Ciel had long gone to bed, and he hadn't seen a glimpse of the butler all night. He knew how Sebastian operated. A couple of hours meant a couple of hours, even if Agni had told him to take as much time as he needed. What had him even more concerned was the fact that the Phantomhive butler was nowhere to be found. The servant's quarters looked as though nobody had set foot in them in weeks, and there was no indication that Sebastian had gone into any of the other rooms in the house all day.

For a moment Agni worried that the demon had slipped out of house to continue the earl's investigation, making anger and annoyance threaten to flare at the idea that Sebastian was still trying to push himself in the state that he was in. Demon or not, Sebastian had looked like he was ready to drop the last time Agni had seen him, and his feelings made him desperate to ensure that he stayed fit and healthy.

Those thoughts were quickly pushed aside, though, when Agni heard a sound coming from the wine cellar. Something was moving around somewhere deep within the bowels of the room, filling it with the bell-like tolling of bottles moving and gently colliding with each other. At first, he thought maybe a cat or some other small animal was down there making the noise, but the thought was forced out of his mind when he heard a noise rising above the almost song-like clattering: panting. It only seemed to grow louder as Agni took a step forward and pressed his ear against the wooden door. One of the floorboards underneath his feet let out a soft croak, and everything beyond the door went silent.

"Sebastian?" Agni called out quietly, "Is that you down there?"

The butler barely had time to process it before inhumanly fast footsteps scampered up from the depths of the cellar and something heavy collided with the door with a deafening thump. The vibrations were enough to send him tumbling backwards onto the floor, gasping with shock. Agni didn't dare to tear his gaze away from the door, lying in the middle of the hall until he heard the ominous creaking of footsteps making their way back down the cellar steps.

Exercising a bit more caution, Agni managed to stand up and inched back over to the door. There wasn't a doubt in his mind that Sebastian was down there, that it was he who was panting, and that it was he who had thrown himself against the door. Whether he had meant to frighten him off or had been trying to attack him, he didn't know, and a wiser man probably would have turned tail and run, but Agni was determined to get to the bottom of the mystery behind his friend's ailment. Whether he was about to face a poorly servant or a feral demon didn't matter.

The heavy wooden door opened with a forceful tug followed by an eerie groan that resonated from its hinges. Agni took a step back as he let go of the latch and peered into the doorway. The darkness inside was thinned by the amber glow of a lantern sitting at the bottom of the steps, and he could just barely make out the end of a shelf that was fully stocked with bottles of wine. Slowly, he made his way down, the old wooden boards of the steps protesting against the butler's weight with rat-like squeaks until his feet made contact with the wooden planks of the cellar's floor.

As he lifted the lantern by its handle, Agni's ears picked up the sound of the panting that he had heard earlier. He shined the light at the area surrounding him, only to be met with shelves of wine; some riddled with empty compartments, and others that had been left undisturbed, likely for special occasions. He remembered coming down here a time or two to find a vintage that partnered well with his master's meals, and he recalled seeing an area that was just out of sight from the bottom of the stairway. In all likelyhood, that's where Sebastian was hiding, and he realized just how accurate his guess was when he saw a pair of glowing red orbs peering at him through the darkness of that corner, sending shivers down his spine.

The layers of shadows peeled back as Agni approached with his lantern, gradually filling the secluded corner with a warm, golden glow. The darkness parted, revieling the demon hidden within, and Agni's jaw dropped at the sight before him.

Sebastian lay trembling close to one of the shelves of wine, stripped nude, with his gloves, tailcoat, shirt, and trousers draped casually over it. Despite how cool the air in the wine cellar was, he sweated profusely; far worse than when Agni had seen him last. His exposed skin almost appeared grey, and his entire torso seemed to expand and contract as a single unit with each heaving breath he took. He tossed and turned restlessly as his hands and feet mangled a thick woolen blacket that was spread beneath him. Moans and whimpers of pain and desperation escaped the demon as his head back and his back arched, throwing his hair into a disheveled mess. Agni struggled to keep his eyes from lingering over the demon's penis, which stood painfully erect against his abdomen, slick with a combination of pre-ejaculate, sweat, and semen.

An ache settled in Agni's chest at the sight. Whatever was happening to him, Sebastian looked like he was in agony, and there was nothing he could do to ease it. How long had he been left like this? How long could it possibly go on, and how long could the demon possibly endure it before his body would give out, if such a thing were possible?

"Sebastian..."

Though it'd left Agni's mouth at a scarcely audible sympathetic whisper, the demon's eyes flew open at the mention of his name. Glowing, slitted eyes bore into the butler's as he went still, save for his breathing. Agni wasn't sure if he was taking in the awkwardness of the situation, or simply unsure if his fit had conjured up some sort of hallucination, but eventually he found a enough threads of sanity still connected in him to form a response.

"Agni?"

The butler flinched at how soft and hoarse the demon's voice was. It was like he wasn't completely there, like he was a shadow in a world plagued by his anguish. His gaze was paralyzing, despite how exhausted he looked. It was as if the flames of Hell swirled within them, but Agni did his best to push that aside as he lowered himself next to Sebastian.

It appeared as though every one of his senses was overwhelmed. The demon's eyes snapped shut as the lantern drew nearer, the light shining through the glass causing them to squeeze shut as tightly as they could. His writhing had grown so intense that he was gradually slithering his way off of his makeshift bed, as if the wool had been lined with needles that were jabbing into his skin. His nostrils flared, picking up the sickeningly oily smell of the burning lantern, and the overpoweringly sweet smell that seemed to radiate from Agni's core, causing the demon's teeth to morph into fangs as his mouth began to water.

Of all the people to see him like this, he didn't dare to dream Agni ever would. And the obnoxiously suductive scent that was radiating off of him made Sebastian feel as though he was being cooked alive over a raging fire.

"What's happing?" Agni asked, "What's wrong?"

Sebastian searched whatever scraps he had left of his thoughts for an excuse; something that made the matter seem less serious than it actually was, but he knew. He knew Agni knew what he was, and he knew Agni would know if he lied to him, forcing him to drop his head back against the floor in defeat.

"H-heat..." he managed to hiss out.

Agni furrowed his brow in confusion. Heat? What did he mean? It was practically freezing in the cellar, yet, in his current state, Sebastian looked as though he'd been tossed into a scorching hot desert to die. However, his mind quickly put the pieces together as the fingers to one of the demon's hands coiled around his throbbing erection. All at once, Agni felt the heat that had been building below the skin of his cheeks explode across his face.

Sebastian was _in heat_ , and his entire being was yearning for a mate.

Still, even as he watched the demon struggle to deal with his erect member, Agni couldn't help if the thoughts that were starting to consume his mind were really the best course of action. He could take him. Right here and now, he could take him and do everything Sebastian's instincts were screaming for, then maybe it would put an end to the demon's suffering... _Maybe_. And that seed of doubt was the only thing holding him back, because if he was wrong, Sebastian most likely wouldn't forgive him. Next to Soma, the demon was his closest and dearest friend, and he didn't want anything to ruin that.

Agni gently rested one of his hands on the demon's shoulder, flinching as he realized Sebastian's skin was as cold as clay. The touch of the butler's hand drew a small, desperate whine from the demon as he ceased his masturbating and met his gaze.

"What do you want me to do?" Agni asked.

The question had Sebastian momentarily stumped. In the past, whenever someone discovered that he was in heat, usually demons, they would take him right then and there with little regard as to whether he wanted to mate with them or not. Nobody had ever seeked his permission to mate with him. They just did it. This typically resulted in pregnancy, but none of them had ever been successful. He would only manage to carry them for a few weeks to a couple of months, at the most, before he'd miscarry due to an intense battle or a lack of food. Male demons were prone to complications with pregnancy and childbirth, regardless, and Sebastian had grown content with that fact over the centuries, but it had also led to him being very reclusive; hiding away in remote, seculded, or otherwise private places whenever he was in heat to decrease the chances of him ever being found. All of which was what had led to his current prediciment: having to deal with a ruthless, unbearable heat that would eventually kill him if he didn't find a mate.

And Agni...

What exactly did the butler mean to him? As a demon, Sebastian didn't really feel any sense of friendship or camaraderie towards him. Agni was a human, a fellow butler, a last-ditch effort for a meal if it came down to it. Not exactly what his kind would call a suitable mate, unless they lusted them enough. But as he stared into the butler's icy blue gaze, he saw something. Something that he'd never seen in the eyes of anyone he'd mated with in the past.

The funny emotion that humans called love.

Is that what he was missing? Would his heats become more bearable if he were to mate with someone who actually loved him? Doubtful, but Sebastian knew one thing for sure. What he wanted, what he _needed_ , right now more than anything, was Agni.

"Help me..." the demon's voice shook, fighting to keep his words at an exhaughted whisper, rather than let it raise to the desperate whimper that threatened to slip from his throat, "Do what you must. Just make it stop."

Sebastian rolled back onto his back, spreading his legs slightly, exposing his still painfully erect member and his anus, which was dilated and open; a clear message that told Agni _exactly_ what the demon wanted.

Blushing fiercely, the butler stituated himself between the demons legs and pulled the throbbing erection into his mouth, drawing an almost musical whine from Sebastian. At first, all Agni could make out was the confusingly briny, bitter, and sweet taste of the fluids that had been coating the organ, nearly bringing on the urge to vomit, but the more he sucked as he started pacing himself, the more those tastes started to melt away. Underneath those slick secreations lay the soft skin of Sebastian's shaft, rippling with thick veins that pulsed against the inner walls of his mouth. As he came up, he let his tongue explore the head of the demon's penis, twirling over the smooth, sensitive skin and occasionally licking the slit that was secreating the strangely sweet yet bitter taste of his semen.

A powerful vibration briefly pulled Agni from his concentration. From either side of his head, Sebastian's legs trembled with the butler's movements. Talon-tipped hands glidded effortlessly across the rippling features of his torso, pausing only briefly to caress his breasts, pinching and rubbing circles around his nipples as he relished in the waves of pleasure he was riding. His pearly fangs glistened in his mouth as moans of pure pleasure poured from his throat. The agonized, tormented expressions the demon had been wearing before had melted away into one of absolute bliss.

The sight had Agni so taken that he didn't notice one of the demon's hands creeping across his shoulders until he felt the fingers lace through his hair and curl up into a fist. In one swift motion, Sebastian shoved his head down with tremendous force, thrusting his member deep into the butler's throat, causing him to gag. The demon arched his back as his orgasm built, his moans reaching a crescendo as he spilled his seed before Agni realized what was happening.

"A little warning would have been nice..." the butler growled, spitting the semen onto the floor. His glare only lasted a few seconds before falling away as he took in Sebastian's state.

The demon lay limp across the woolen blanket, a blank look in his eyes as his chest rose and fell rapidly as he tried to catch his breath. Sebastian looked as though he'd experience the biggest relief in ages. He was still for several moments before his eyes moved back to the butler. There was less desperation in them now, but something in them told Agni that the demon was still not fully satisfied.

Looking down, he could see that Sebastian's anus was still dilated, open, and hungry for attention.

"More?" he asked teasingly, a hand gravitating towards the orifice.

Sebastian's eyes strained to see where the butler's fingers were heading, and he mentally chuckled. If only Agni knew of the sick things demons resorted to in order to ease their heats. While he felt eons better after being sucked off, it would take more than a couple of measly fiingers on top of several more orgasms like the one he'd just had before he would be fully satisfied, but he was willing to let the butler try.

The wetness was the first thing Sebastian noticed as one of Agni's fingers slipped inside him; the inner walls of his anus made slick with its own natural lubricant. A slightly pleased hum rumbled in his throat as the butler slowly started pacing himself.

"More," he moaned.

Agni immediately obliged, and the demon's moans deepened as a second finger was inserted, brushing against his prostate in the process. The reaction was almost instant as Sebastian felt himself begin to harden. He didn't bother trying to deal with it, and it didn't seem he would have to as Agni lowered himself back between his legs and pulled his member back into his mouth. His body's reaction was almost instant. His legs and shoulders began to tremble as his core and haunches tensed, all of them joining together and growing in intensity as he felt his next orgasm build.

"More," Sebastian groaned as one of his hands found its way back into Agni's hair, playing with one of the long tails that was draped elegantly over his shoulder while his other hand found its way back to his chest to tease one of his nipples, adding to the pleasure coursing through him.

But Agni was on his guard this time, and he was prepared as he heard the demon's breaths quicken and the hand that was fiddling with his hair moved to the back of his head. While he was no match for Sebastian's strength, he was able to better prepare himself as his head was thrust down once more and the demon's hips bucked as he came. Little came from it though, as his previous orgasm had drained him of the rest of his semen. However, it did manage to clear the heat from his head, and he found that he was able to think more clearly as Agni pulled the demon's member from his mouth.

"More?"

Sebastian felt the butler's fingers curl within him, continuing their persistent teasing at his prostate, keeping a steady stream of pleasure flowing through him. He wanted more. _God_ , how he wanted more, but the memory of pointless pain and infuriating amounts of his own blood caused him to lift a finger of pause.

"I can't..." the demon muttered, mentally cringing at the words.

Agni's brows knitted in confusion, "Is something the matter?"

Slowly, Sebastian managed to sit up, only to have the combination of his heat and exhaustion force him to slump against the butler.

"I just can't. It's pointless."

Agni was taken aback by the demon's words. Pointless? It had only been a short time before then that Sebastian told him to do what he must to alleviate his heat. He'd pleaded for more. He could have thrusted into him right then and there, but he didn't, thinking that in doing so he'd ruin one of his most valuable friendships. And now he was saying that he didn't want it? No, rather he _couldn't_ have it? In all his life, he only ever knew of one reason why anyone would keep themselves from going so far.

"Forgive me if my assumptions are incorrect," the butler piped up, "But does being a demon in heat mean that you are able to conceive a child, even if you are a man?"

He felt Sebastian nod against his shoulder.

"That's why I can't do it," the demon responded, "I live a dangerous life working for the Queen's watchdog, and I've lost too many already. Just leave me here. I should start feeling better by tomorrow."

An ache settled in Agni's heart as he listened. Sebastian had mated before. He'd conceived children before, and he'd lost all of them. He could only imagine the pain the demon must have felt. Maybe it was one of the reasons why he was so protective of Ciel, aside from their contract, but he knew that Sebastian wouldn't be able to run from what was inevitably going to happen forever. Sooner or later, he'd mate during one of his heats and fall pregnant again. It was only a matter of time.

"Sebastian..."

Agni tilted the demon's head up, caressing the side of his face with one hand while lacing his fingers in with his with the other. The heavy-lidded gaze that he was met with seemed to tell him that Sebastian was resolved that he would rather have his heat kill him than risk conceiving and miscarrying another child.

In one fluid motion, Agni pressed his lips softly against the demon's. He felt a purr rumble in Sebastian's throat, signaling that the display wasn't unwelcome. The purrs deepened as the butler's kisses trailed along his jawline, down his neck, and across one of his shoulders. He could already feel the demon's member growing hard against his abdomen as he pulled him onto his lap. Sebastian's skin was like cool porcelain against his lips; pale and cold, but still so smooth and beautiful.

"You live a good life with your master," Agni stated, "And if anything happens, I can be there for you when you need me, if that's what you want, but don't deny what your body needs right now."

Sebastian was silent as he dropped his gaze to the floor. The members of his family were descendants of Raum, a well-respected earl of his realm, and also a raven demon. Members of his family were known for having multiple births; twins, even triplets, at times. Even if he managed a successful pregnancy, labor and delivery were garunteed to be difficult. Deep down, however, he was up for the challenge. It was still possible for him to have what he'd been wanting for eons now: heirs of his own, even if they were begot by a human.

"Then I'll try," the demon finally stated with a sigh, "but if I can't do it... if I lose it again..."

Agni smiled, "Try not to think about that. Think positive thoughts. Don't wrap yourself up in what-ifs."

Sebastian surpressed a laugh as he laid himself back down on the blanket. It's what he liked about non-English types, with their different ways of thinking, open-mindedness, and methods of enlightment. Combined with Agni's kind, caring, and compassionate nature, it was almost like an aphrodisiac to him; incredibly soothing, yet exciting all at once. He loved giving people with such thoughts the benefit of the doubt, even when his own swirled with chaos and curruption, but with Agni it was almost inspiring, making him want the butler to be right; that he would conceive and carry successfully this time, and be able to bring life into this world.

As Agni began to disrobe, Sebastian's heat flared. The clarity that he'd been given just minutes ago rapidly turned into a muddled fog of intense need. The cellar felt like it was an inferno, and the blanket felt like it had turned into a bed of knives. All of these sensations were only made stronger as Agni took off his sherwani, filling the area around him with the intoxicatingly sweet scent that the demon had smelled earlier on. It overwhelmed him, snatching the air out of his lungs and anchoring every part of his body to the floor. With every moment that passed, the fog filling his head thickened until he felt like he was gazing into a void; an endless, tormenting darkness that he wouldn't be able to pull himself out of.

Before he could give in to that void, however, the darkness suddenly gave way as Sebastian felt Agni pushing himself into him. A slight gasp escaped him as the muscles of his anus stretched to accommodate for the butler's surprising size, driving deep inside him; seven, maybe even eight inches with an impressive girth until their hips finally connected.

"Does it fell all right?" Agni asked, his voice strained by the tightness of the demon's orifice, "I'm not hurting you, am I?"

Sebastian shook his head. Whether it actually hurt or not was irrelivant to him at this point. The demon knew the only way to rid himself of his heat by dawn would be to breed. Any pain he was feeling was only added to the pleasure that pulsed through him as the butler pulled back slightly and thrust back into him.

Sweat quickly started to build along Agni's brow as he started pacing himself. Sebastian's skin might have been as cold as ice, but inside he was boiling hot; the intensity alone already encouraging the butler's orgasm to come forth, but he held onto it. The demon had appeared to be on the brink of death just waiting for him to undress. Coming now would likely do little to best his heat.

Moving carefully, Agni pulled Sebastian into his arms and sat him up on his lap. The demon let his head fall back as he let out a passionate moan as he felt the butler's shaft move even deeper, pulsing and throbbing, igniting his lust and driving him to move on his own as he began pacing himself.

Agni wrapped his arms around him, caressing his back as he did so. He smiled as Sebastian's purring resumed, pressing soft kisses against the demon's exposed neck as he listened to their reverberating chorus. He almost couldn't hold back his joy as he felt Sebastian mimic his actions, pressing his chilled hands against his back as his lips trailed down the side of his neck and over his right shoulder. It seemed as though the demon was returning his affections, making any lingering feelings of awkwardness from when Agni had first found him begin to fade.

His relief was short-lived though as Agni found himself being pulled out of his thoughts by a searing pain tearing through his right shoulder. As the bulter strained his eyes to find the cause, an inhuman, gutteral growl escaped the demon on top of him as he quickened his pace. It was then that Agni realized that the pain he was feeling was Sebastian biting into his shoulder, sinking his fangs deep into the firm muscle there. He felt the sting of the demon's nails digging into his back, raking what felt like whole chunks of flesh off of his ribs and shoulder blades.

So many questions hit Agni at once. Was Sebastian all right? Was doing this because he was in pain? Was it instinct? Was it just how demons like him behaved while they mated? All of his uncertainty sent a flicker of fear coursing through the butler, something the demon must have picked up on as he bit down even harder, moving faster, driving Agni's member as hard and as deep as he could into himself as the air of the cellar began to fill with the sound of slapping skin.

Sebastian's movements made it impossible for the butler to hold back his orgasm any longer, and Agni returned the demon's gestures in earnest, biting into one of his pale, sweat-slicked shoulders and dragging his nails across his back as he spilled his seed deep inside him with a shudder.

All at once, the demon's pace began to slow until his hips rocked subtly against Agni's. The growls died down into labored breathing, sending bursts of air down his back, agitating whatever scratches Sebastian's nails had left in their wake, and the demon's hands had gone back to their previous state of caressing the butler's back. His body tensed and a shiver ran through him in an orgasm before letting out a jarring noise that sounded like a mix between a snarl and a roar; a noise that would even make the most fearsome tiger cower in fear.

After a brief moment of pause, Sebastian pulled his fangs out of Agni's shoulder and practically collapsed against him.

Agni felt paralyzed with worry and confusion. His heart felt like it was trying to pound its way out of his chest. He felt like he had just seen Sebastian for what he truly was: a demon, a monster, a beast, not human, even when he acted like one; just mimicking in order to seamlessly blend in. The Phantomhive butler was a creature from a place that he'd been fighting to gain distance from ever since his prince had given him his second life...

And yet, somehow, Agni still found it beautiful, making him smile as his exhauation caused the demon to drift off to sleep.


	2. PART 2

**PART 2**

 _"You disappoint me, son. By no means are you the eldest of my offspring, but you should know well that doesn't mean that I expect less from you. Your brothers and sisters have brought forth many heirs to Raum's name, yet you can't manage to successfully carry one. Learn your limits, boy. The children you bear are worth more than any contract. Remember_ _that."_

 _"Yes, father..."_

 **000**

Sebastian couldn't help but wrinkle his nose in distaste at the memory of his father's words. In the beginning, when he and Ciel had first formed their contract, the young earl had once asked him why demons didn't sleep. Part of it was because they simply didn't have the need to sleep like most living creatures, at least not as frequently or nearly as long, but memories also played a part in his state of never-ending alertness. To be asleep was to be vulnerable, and to be vulnerable was to be an open target. Not just to other demons and the horrific creatures of his realm, but to his own mind and the nightmares that lurked within it.

His father didn't understand. It wasn't the pain of losing his unborn children that haunted Sebastian, it was _how_ he'd lost them, as well. His father would never understand the efforts he had gone through to manage a successful pregnancy. He cursed at the humans that were so quick to terminate their pregnancies as he struggled to maintain his, because of the many things Sebastian hated in the universe, of all the things he loathed, his own flesh and blood was _not_ among them.

Sebastian tried to relax as he remembered what Agni had said. His life as a butler was a lot cushier than the life he lived in his own realm. Sure it was dangerous working for the Queen's watchdog, but if he could somehow manage it, avoiding any pointless battles or pulling risky stunts, then maybe... just maybe he could do it. If the lifespan of one human felt like a fleeting moment to him, then being wary of nine miniscule months would only be a fraction of that.

But first was the waiting game; the two week wait to see if he'd even conceive.

Sebastian pulled himself from his thoughts as he heard something stir from behind him, and a hand rested on his shoulder.

"Sebastian, are you awake?"

The demon felt his heart skipping inside of his chest as Agni's voice brought back memories of the night before. Much of it was blurred by the intensity of his heat, but he knew what he had done. Hell, he could still smell it within the damp, dank air of the cellar; the lingering stench of sex. He had mated with Agni; a human, a fellow butler in his own right. He didn't want to be awake. He didn't want to gaze upon the aftermath of what had happened, including whatever state he'd left his new mate in. If it weren't for the countless thoughts, hopes, and worries swirling around inside his head, Sebastian would have been swallowed up by his shame at tarnishing his aesthetic.

Eventually, he let out a slow, calming breath, "Regrettably."

The hand resting on Sebastian's shoulder slid over to caress his chest, and he felt the firm muscle of Agni's chest press against his back. Part of him wanted to pull away from the butler. He needed more time; time to let the events of last night sink in, and time to brace himself for what might be soon to come. The other part of him, the instinct he ultimately allowed himself to follow, made him slide closer and press himself against the butler, relishing in the warmth and comfort brought to him by his new mate as he inhaled that intoxicatingly sweet scent that danced beyond his shoulder.

"How are you feeling?" he heard Agni ask.

"A lot better," Sebastian answered with a sigh.

The statement was more true than the demon had realized, at first. The merciless heat and unyielding arousal he'd been consumed by earlier had dulled into an ever-so-slight fever and a slight ache in his anus cause by the friction of mating. The fog that had been muddling his thoughts had cleared. The only symptoms of his heat that still seemed to linger was his sexual appetite as he felt his body hunger for more of what Agni had offered earlier.

Slowly, Sebastian rolled over to face the butler. The first thing his eyes settled on was the deep bite wound on his shoulder, already dry and scabbed over, a dark bruise surrounding the skin around it. The sight of the wound seemed to react with the bite wound on the demon's own shoulder, making it burn and ache with its presence. Even so, the pain wasn't enough to provoke any response from Sebastian. If anything, Agni's wound looked more serious and painful than his felt.

The demon let out a mock hiss, "Best to wash that up, and soon. You wouldn't want that to get infected."

Agni cracked a small smile, "Not to worry. I can hardly feel it. Besides, I think those claw marks you gave me hurt more than that affectionate nip."

"I am terribly sorry. I must have gotten carried away."

The affection in Agni's gaze deepened as he rested a hand against Sebastian's cheek. The warmth of the butler's tanned skin flowed through him, causing a placid smile to creep along his face. His touch was like a drug; addicting, making him crave it more and more. The demon's arousal flared, his erection returning with a vengeance in response. It only confirmed that his heat hadn't passed just yet.

Agni must have picked up on this as chuckle rumbled deep in his throat, "Still not fully satisfied yet, huh?"

Sebastian shook his head. He knew it took more than one round of sex with a mortal to rid a demon of his heat. Typically, it took twelve to twenty rounds before it wouldn't affect him anymore. The only thing Agni had going for him was that he had caught him when his heat was at its peak; when his yearning was at its highest intensity and was easier to satisfy.

Now that he was thinking more clearly, without the distraction of desperation and every sight, sound, smell, and touch, the demon could take everything into account before proceeding.

"What time is it?" he asked.

Agni shrugged, "Not even dawn. Four or five in the morning, perhaps?"

That was all the answer Sebastian needed as he sat up and moved until Agni was pinned beneath him.

"We've got a little time."

 **000**

The days that followed after Sebastian's heat had passed were the longest he'd ever endured. Anxiety and dread followed him every moment as he waited for any one of the numerous symptoms of pregnancy to make itself known.

His father had always told him that he would know long before he'd experience any symptoms, but Sebastian had proven time and time again that the things that were expected from most other demons didn't apply to him. He'd always been a little strange, even amongst his own kind. From his taste in masters to his love for cats, and the fact that he was far more gentle and compassionate in his interactions in the mortal realm compared to most demons that just apathetically conducted business and moved on. In almost all cases, Sebastian knew he carried an aesthetic that was unexpected from a demon. Most likely, his pregnancy would follow a similar trend, so Sebastian kept his wits about him for anything and everything that seemed out of the ordinary for him.

In this time, Agni was in a similar state as Sebastian. He was anxious, but also excited. The fact that the demon was possibly carrying a child, _his_ child, made his heart swell with pride at the very thought. He knew he shouldn't get his hopes up, especially if something went wrong or if one of their masters didn't approve, but just the idea excited him, and deep down he knew, as both Sebastian's mate potentially the soon-to-be father of their child, he'd accept whatever consequences came his way; for better or for worse.

One week passed, then two, and then three. At one point, Sebastian started to think he hadn't caught that season. Maybe the timing was off. Perhaps he and Agni had gone overboard that night in the wine cellar, having engaged in about four rounds of sex before the dawn, and several more throughout his and the earl's stay at the townhouse. Or maybe it hadn't been enough. Agni was only human after all, and the seed of a human wasn't quite as compatible as that of the demon's own kind. Perhaps Sebastian had gotten off lucky, having Agni there to alleviate the symptoms of his heat and dodging the bullet of conception in the process.

However, any possibility of that was eliminated after the fourth week arrived.

In humans, a missed cycle or bouts of nausea came with the territory of pregnancy. Maybe a bit of bloating or moodiness thrown in.

Not for demons, especially the males. No, the first thing to tip Sebastian off was his hunger. What was normally just a distant yearning for a snack had grown into an insatiable, persistent, almost agonizing hunger that plagued his entire being; one that normally only came about after centuries of starvation... or if _something else_ required sustenance from him. In that moment, every soul that came near was tantalizingly mouthwatering to him. Finny, Bard, and Mey-Rin had nearly become his first victims a few times before Sebastian caught himself.

The second sign to alarm Sebastian came one night while the rest of the house was sleeping. He was thankful for that, or else they'd all have plenty of questions for him as to why he was mindlessly bringing _carrion_ into his master's house. It felt like he'd blanked out for just a second, yet the mansion went from being polished to a spotless shine to being a den he'd find in his own realm, lined with mangled fur, bones, and rotting flesh; all woven together with everything from bits of rope, to mud, to straw from the stables, and he'd done it all in the course of four hours. Thankfully, he snapped out of his haze and cleared everything out, returning the mansion to its previous state in a matter of minutes, and nobody was the wiser. However, Sebastian couldn't help but loath himself for not being able to resist the sudden urge to nest so soon.

The third sign was more subtle than the first two, but still didn't go unnoticed, and that was the deep longing to be near his mate. Sebastian hadn't seen Agni since he and Ciel had returned to the Phantomhive manor, and it tortured him; a primal desire demon's held when they were in heat or carrying offspring to bring comfort and protection. Sebastian wasn't weak, so he felt he could make do with or without Agni's presence, but if given the choice he wouldn't pass up the opportunity to be with his mate.

The fourth sign came less from him and more from Pluto, the blasted demon hound his master had insisted he take in and train. Pluto had always clung to Sebastian, sometimes emotionally, sometimes physically, but now he was more inseparable than ever. The hound would stay as close as he could to him and rarely strayed unless specifically told by the butler to do so. What's more, Pluto became incredibly protective of him, snarling threatening to pounce at anyone who came near, even at Finny who often played with the hound while he was out gardening. The young gardener inquired about Pluto's sudden change of behavior, and the only explanation Sebastian could conjure up for the young servant was that it was tied to a dog's sense of loyalty, and that being a _demon hound_ didn't help the matter.

The final sign for the demon was less of a sign and more of a confirmation. Agni and Pluto were things he could easily come up with excuses for, but his persistent hunger and urge to nest were definitely symptoms that he couldn't ignore. Unlike in his own realm, there weren't any demons he was close enough to that could confirm if he was expecting. There was only one method Sebastian knew of that could help him confirm it in the human realm.

Six weeks after his heat, two weeks after the symptoms began showing themselves, Sebastian ventured into the forest surrounding the manor and found an old beech tree. He shaved the bark off a small section of it, splintering it in some areas, and urinated against the exposed wood; one of the few functions he could force his human form to do if he so desired. Once he had finished, he crouched beside the tree and waited.

It didn't take long before Sebastian got the confirmation he needed. It started off slow, but gradually the wood of the beech tree started to darken in the areas that were wet until they were pitch black, like an inkwell had been emptied against it.

Sebastian let out an airy sigh. According to his father, this was the most accurate method for demons to detect their pregnancies in the human realm, but he never had to use it until now.

In any other circumstance, nothing should have happened. Now, there was no denying it...

 **000**

Agni had never snuck a horse out of the stables so quietly before in his life. He thought he had put his days of sneaking out behind his master's back behind him, but when he had received a letter from Sebastian, by owl no less, telling him to meet him in the woods that sat between the Phantomhive manor and the townhouse, he knew it was something neither of their masters could know about.

He couldn't help but worry, though. Would this be about what happened between them all those weeks ago? Was Sebastian upset? Did something happen? Was he about to deliver the final news about his possible pregnancy, or were they meeting for an entirely different reason? Either way, Agni knew he had to see this through to the end, both as Sebastian's mate and his best friend.

The butler rode swiftly, taking vacant side streets and deserted roadways to avoid being spotted. Flashes came back to him of all the times he snuck out before the curry competition, and he constantly found himself tossing glances over his shoulder to make sure his prince wasn't looking and he wasn't being followed. Cobblestone eventually turned to dirt, and Agni started keeping his eyes peeled for the place Sebastian had chosen to meet him at; an abandoned stable that the demon often used for his own horses.

Eventually, he saw the glow of a lantern in the distance, growing closer and brighter as he and his horse came up on it. The lantern illuminated a wide, open door, and as he walked his horse to a nearby post, Agni could see the shape of a tall, white horse standing behind a stall door in the shadows within. The building itself looked old and rotting, like nobody had really bothered to keep up on it in decades. Why Sebastian trusted it to house such a brilliant steed was lost on him.

Agni quietly dismounted his horse and approached the stables with caution, taking the lantern with him as he did so. The white horse inside stared him down with ears pulled back with unease as it shifted around. As it came into the light, the butler could make out its pale blue eyes that seemed to stare deep into his soul. There was no name plate for the horse anywhere, just a crudely carved letter "P" on the edge of the door. Agni tried to reach out and pet the anxious animal, only to have it respond with an alarmed squeal before it skittered away from his hand.

A small thudding from the next stall over caught his attention. There were two horses on either side of the white one. A thin black mare that looked like she'd given up on life a long time ago stood eerily still in the middle of her stall with her head lowered, as if she didn't even have the strength to hold it up anymore. Again, the horse had no name, just a crudely carved "F" on the edge of the door.

On the other side of the white horse was a muscular chestnut stallion that seemed to be riddled with scars from head to hock, this one with a "W" etched into the stall door. The horse glared at Agni with a supernatural amount of rage and disdain. His ears were flattened against his head, almost to the point where it looked painful. As the lantern cast its light over the stallion, the rust-colored hide seemed to turn a deep shade of red, as if the horse was covered in blood.

The fourth and final stall housed a rather gentle-looking, long-legged flea bitten mare with a grey muzzle. A single blue eye seemed to cut through him like blade while a round, black eye looked upon him with a sort of fondness that Agni couldn't quite place. Unlike the other three horses, this horse's stall had a name carved into it, but Agni had a strong feeling that the name didn't belong to the horse.

'Death'.

He should have made the connection a lot sooner. The horses belonged to the infamous four horsemen of the underworld: the red horse of War, the black horse of Famine, the white horse of Pestilence, and the pale horse of Death.

That fact should have sent Agni running, but he stayed routed in his spot. The fact that the lantern was here, of all places, meant two things. Sebastian was here, and he was in affiliation with the four horsemen, if he wasn't one himself.

"Sebastian?" the butler called out, "Are you here?"

The stables were quiet for a split second before a voice responded from the hay loft above, "I'm up here, Agni."

Agni let out a sigh of relief as he hurried up the old wooden ladder leading up to the loft. Sebastian met him at the top and helped him into the pillows of hay, which he'd pulled apart from their uniform bails in his nasty nesting habit. The lantern was hung well out of reach of the hay above them, casting the loft in a warm golden glow.

"I have so many questions," Agni stated, seating himself on a sturdy bail.

"I'm sure you do," Sebastian responded, seating himself across from him, "Where would you like to start?"

"It didn't take me long to make the connection with the horses. Either you have a sick sense of humor, or you're one of the four horsemen."

Sebastian let out a chuckle, "I've been told I have a rather playful sense of humor, but I didn't call you all the way out here to play tricks."

"Well, you've never really been one to lie before, Sebastian," Agni fidgeted in place as he glanced down to the four horses below, "So... which one is yours?"

"The white one. I do apologize for Leper's skittishness. If the world's not due for a plague, she's rather just keep to herself."

Agni blinked at the demon, "You named your horse 'Leper'?"

"Better than Psoriasis, Tuberculosis, or Influenza."

"So you're Pestilence, then? Is that what you're really called?"

"Yes... and no. Demons don't really have names, you see, unless they're nobles. Raum, one of Hell's earls, is actually my great grandfather. Between my grandfather, my father, and everybody born in between, I'm not all that high up on the family VIP list. So the best name I could make for myself was being the second horseman of the underworld. Don't worry, I can't start a plague by touching you, or sneezing, or anything."

A thousand questions raced through Agni's mind; questions about Hell, and death, and demons, and the gods, but the whole thing seemed like a tangent from the real reason for this meeting. There seemed to be something unusual about Sebastian's demeanor. He appeared to be apprehensive about something; prickling with worry and unease. If anything the four horsemen discussion was his way of stalling for a time.

"So... whatever did come from that night you were in heat, Sebastian?" he asked.

The demon was silent for a moment, carefully thinking through his response.

"Nothing for the first three weeks, at least," he said, "I didn't sense a change, nor did I feel any different. It wasn't until about two and a half weeks ago that I started seeing the signs, and it's just been confirmed."

Agni felt something in his chest tighten, something like joy, pride, and excitement stuffed into one inexplicable emotion.

"So... that means you're..."

Sebastian gave a weary smile and nodded.

"I'm pregnant."

* * *

 ** _AUTHOR'S NOTE 9/29/2019_**

 _Sorry for the SUPER LONG wait for an update! After recent events unfolded in the manga, LITERALLY LESS THAN A WEEK AFTER i FIRST POSTED THS FIC, I went on like a 7 month long hiatus from writing. That, and I also got distracted. No matter what happened in the manga, THIS FIC SHALL GO ON! I'm glad to see people are really enjoying this fic. Thank you guys for all the love and support you've been putting in the comment section._


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